A city council is deciding whether or not to spend additiona

A city council is deciding whether or not to spend additional money to reduce the amount of traffic. The council decides that it will increase the transportation budget if the amount of waiting time for drivers exceeds 24 minutes. A sample of 30 main roads results in a mean waiting time of 27.81 minutes with a standard deviation of 3.43 minutes.

b.

Compute the value of the appropriate test statistic. (Round intermediate calculations to 4 decimal places. Round your answer to 2 decimal places.)

c-

Calculate the critical value at a 5% level of significance. (Round your answer to 3 decimal places.)

Solution

(b) The test statistic is

Z=(xbar-mu)/(s/vn)

=(27.81-24)/(3.43/sqrt(30))

=6.08

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(c) It is a righ-tailed test.

Given a=0.05, the critical value is Z(0.05) = 1.645 (from standard normal table)